I guess for "router" you meant your "internet modem", and how to be sure that no one is accessing it from outside. Well it's a risk, so you can spend a lot of

I guess for "router" you meant your "internet modem", and how to be sure that no one is accessing it from outside. Well it's a risk, so you can spend a lot of money to minimize the risk, but you can't get rid of it. You can try to minimize the attack vectors at WAN side: - drop incoming connections from WAN, firewall - no ICMP answers - no admin interface, being it html, telnet, ssh (some routers bypass the firewall on these services) - no default password! - no uPNP, so malware at LAN cannot bypass your firewall (but they can still phone home) what else?